The discarded standard required that a skyscraper’s height be determined by calculating the distance from the main sidewalk entrance to the building’s structural top or spire – antennae don’t count. The revised standard measures the height from “the lowest, significant, open-air, pedestrian entrance” to the building’s top. This gave the Trump building an extra 27 feet, because its bottom is now defined as the entrance to the still unoccupied shops along the Chicago riverwalk instead of the main Wabash Avenue door. This brought the tower’s height to 1388 feet, six inches – instead of the previous 1361 feet, six inches.

With the change, the Trump Tower is officially taller than Shanghai’s Jin Mao Building, which fell back to seventh place. The ultimate winner will be the Burj Dubai, set to open January 4 at 2,600 feet tall. That is the equivalent of stacking the John Hancock Center atop the Willis (nee Sears) Tower. The last still reigns as the world’s fifth tallest building.